Effectiveness of Couple Therapy in Practice Settings and Identification of Potential Predictors for Different Outcomes: Results of a German Nationwide Naturalistic Study.

Even though couple therapy is efficacious, there is no improvement in up to 50% of the couples. Also effect sizes found in effectiveness studies in real-world settings are considerably lower than those found in efficacy studies. There is a need to understand more about couple therapy effectiveness in practice settings and the factors responsible for different outcomes. A German nationwide study on the effectiveness of couple counseling including 554 couples applied the same methodology as two earlier studies in the same field. A remarkable consistency was found over the three independent studies in the burden with individual and relationship distress as well as in the rates of improvement. This supports the insight that the improvements reached through couple therapy in practice settings are only about half of the effect sizes reached in efficacy trials. Additionally this study investigated 64 factors, which were found to be influential for relationship quality and stability in earlier studies, for their impact on outcome. Factors present at initiation and termination of therapy were found, which correlate significantly with outcome and with separation of the couple in the follow-up. These factors could be included in prediction models for improvement and separation of the couple. The implications for the practice of couple therapy and for future research are discussed.